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Unread 21-02-2008, 05:28
Travis Hoffman's Avatar Unsung FIRST Hero
Travis Hoffman Travis Hoffman is offline
O-H
FRC #0048 (Delphi E.L.I.T.E.)
Team Role: Engineer
 
Join Date: Sep 2001
Rookie Year: 2001
Location: Warren, Ohio USA
Posts: 4,047
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Re: Team 48-2008-Xtremachen 11

Quote:
Originally Posted by DarkFlame145 View Post
It will five ya lots of pushing power
Actually, I like the halftracks for their balance of traction and maneuverability. The current version with red linatex Brecoflex belts did very well for us at Kettering Kickoff. I'd also like to think they are a more stable driving platform than an equivalent center traction wheels/corner omnis setup - easy enough to turn smoothly, but not TOO easy.

We do have AndyMark Inside - two servo Super Shifters provide direct drive power to the halftracks.


Quote:
Originally Posted by Qbranch View Post
*dancing...* Oh, right.
Don't make Donnell cry. We need Captain Safety in peak emotional status heading into the competitions, lest our pit organization fall apart.

Quote:
Anyhow, nice robot! Moves really nicely, you're driver is quite smooth. Was hoping to see how your driver handled picking that ball up but the scene cut.
Ball pickup is a coordinated effort between pilot and copilot. Our drivers have found that herding the trackball into the nearest solid object, along with the "creatively" soldered 1st generation copper grippers you will see coming out of the crate at Midwest (seriously, if you are a plumber or pipefitter, don't even look), periodically at unnecessarily excessive speed, is the best way to grab the thing. Captured by the gripper fingers, the ball pops right up the sloped top of the bot into the waiting gripper palm. Our bumpers (which I must say look very cool, thanks to the promotions team - thanks to Jimmie Johnson for the inspiration) were fabbed and fitted right before ship, so we have yet to practice with those on - that may slightly affect how the trackball is acquired.

Catching a trackball on the run is still something the drive team is pursuing - we are investigating simple passive changes to the gripper in Midwest to improve grip and trackball acquisition on the go.....and oh yeah, soldered joint strength.

All the arm actuations you saw in the video were manually controlled by the copilot - these are replicated by automatic functions - with the limited practice time we had, we wanted the copilots to see just how much skill and concentration it takes to control a tilting, telescoping, wrist-jointed arm holding an 8-pound trackball 78"+ in the air with a pneumatic gripper. Tis not easy, but it would be required should Mr. Potentiometer and Friends fail us during a match.

By the way, we do hurdle, but there is only one cylinder on the entire bot, for the gripper. We planned for a separate "kicker" to help poof the ball over the overpass, but weight limitations currently prevent that. So we'll just use the tilt and a little creative timing to "throw" the thing over. If we can pare out just a wee bit more spare weight, there's also another passive hurdle assist method we might try.
__________________

Travis Hoffman, Enginerd, FRC Team 48 Delphi E.L.I.T.E.
Encouraging Learning in Technology and Engineering - www.delphielite.com
NEOFRA - Northeast Ohio FIRST Robotics Alliance - www.neofra.com
NEOFRA / Delphi E.L.I.T.E. FLL Regional Partner

Last edited by Travis Hoffman : 21-02-2008 at 06:55.